Ring and roller pulverizing apparatus



April 14, 1964 M. BERZ Re. 25,552

RING AND ROLLER PULVERIZING APPARATUS Original Filed Aug. 2, 1957 4Sheets-Sheet l lNVEN-TOR MAX BERZ 9/ ATTORNEY April 14, 1964 BERZ Re.25,552

RING AND ROLLER PULVERIZING APPARATUS Original Filed Aug. 2, .1957 4Sheets-Sheet 2 ATTORNEY April 14, 1964 E Re. 25,552

RING AND ROLLER PULVERIZING APPARATUS Original Filed Aug. 2, 1957 4Sheets-Sheet 5 INVENTOR ,v Baez M4 Y k I, 9 y (E J ATTORNEY April 14,1964 M. BERZ Re. 25,552

RING AND ROLLER PULVERIZING APPARATUS Original Filed Aug. 2, 1957 4Sheets-Sheet 4 INVENTOR MAX 55/?2 ATTORNEY United States Patent ()fificeRe. 25,552 Reissued Apr. 14, 1964 25,552 RING AND ROLLER PULVERIZINGAPPARATUS Max Berz, Bayerlandstrasse 23, Kochel am See, Germany OriginalNo. 2,944,744, dated July 12, 1960, Ser. No.

675,847, Aug. 2, 1957. Application for reissue Feb. 5,

1962, Ser. No. 172,378

4 Claims. (Cl. 241118) Matter enclosed in heavy brackets [I] appears inthe original patent but forms no part of this reissue specification;matter printed in italics indicates the additions made by reissue.

This invention relates to pulverizing apparatus and more particularlyring and roller pulverizing apparatus wherein material, such as coal andthe like, is crushed and pulverized by action of the rings and rollers.

This application is a continuation-in-part application of United Statespatent application Serial No. 515,404, filed June 14, 1955, nowabandoned.

An object of the present invention is to provide a ring and rollerpulverizer requiring less power input than presently known ring androller pulverizers of comparable capacity.

Another object is to provide a pulverizer wherein the rings and rollersare constructed and assembled so as to provide a self-centering assemblyand in which assembly there are no friction surfaces subject to wear,except the grinding surfaces thereof.

Accordingly, the present invention provides a grinding ring supportedand carried by a base or table within a casing. The table is rotatablymounted and drivably connected to a source of rotary power. In the uppersurface of the grinding ring is formed an annular recess or trackadapted to receive a plurality of pressure rollers, and the rollersurfaces and the track are provided with complementary contactingsurfaces. Each roller is rotatably mounted in a roller race member whichcomprises two concentric rings and each ring has means adapted torotatably support the end portions of each roller shaft and permitlimited vertical movement of the rollers with respect to the roller racemember. A plurality of compression springs are disposed between apressure ring, which engages the rollers, and a thrust ring to provide ayieldable connection between the pressure and thrust rings, and to exertdownward pressure on each roller. The pressure and thrust rings aremounted in the casing so as to be fixed against rotation and at the sametime allow the vertical displacement of the rings with respect to thegrinding table as the rollers planetate in the track of the table.

Other features and advantages will become apparent from the followingdescription considered in connection with the accompanying drawingsforming a part thereof and in which:

FIG. 1 is a sectional view, in elevation, of the pulverizer according tothis invention;

FIG. 1A is an enlarged fragmentary view, in elevation, of the hold-downassembly shown in FIG. 1;

FIG. 2 is an enlarged fragmentary plan view of the roller race member;

FIG. 3 is an enlarged view, in section, taken on line 33 of FIG. 1; and

FIG. 4 is a somewhat diagrammatic representation of a roller and thegrinding track according to this invention showing the movement of therollers under the urging of material to be pulverized.

Referring to the drawings, and more specifically to FIG. 1, designates acasing having a feed tube 12 extending downwardly from the top wall 13of the casing and along the longitudinal axis thereof. A table 14 ishorizontally supported in the bottom portion of casing 10 and in spacedrelationship with feed tube 12. Table 14 is rotatably driven about itsvertical axis by a suitable means, such as a motor 15. A grinding ring14A is rotatably carried on the upper surface of the table 14. In theupper surface of grinding ring 14A is formed a concave annular grindingrecess or track 16.

A plurality of spaced pressure rollers 17 ride in track 16 only one ofwhich rollers, for purposes of clarity, is shown in the drawing. Eachroller 17 is rotatably supported in a roller race member 18, best shownin FIG. 2, which member comprises an inner and outer guide ring 19 and20, respectively. Rings 19 and 20 are concentrically arranged inslightly different horizontal planes and are connected together by aplurality of radially spaced spokes 21 (FIG. 2 Each roller 17 has ashaft 22, the end portions of which are supported by the inner and outerguide rings 19 and 20. Each roller 17 has a hub portion 25 to which ispress fit, or otherwise suitably secured, a bearing collar 26. Collar 26is provided with a peripheral groove 27 which engages a complementaryshaped surface 28A of a pressure ring 28. The surfaces of the rollersand the track may be of any suitable shape; however, it is preferable toprovide a track of partcircular or arcuate cross-section and thesurfaces of the rollers toroidal.

Pressure ring 23 has a plurality of spaced slotted lugs 29 in the outerperiphery thereof into which project tongues 30. Tongues 30 are securedto casing 10 and extend inwardly therefrom into slotted lugs 29 toprevent rotation of ring 28 and to guide the latter in its verticalmovement. Spaced from and above ring 28 is a thrust ring 31 which has aplurality of spaced tongues 32 extending from its periphery, whichtongues project into a plurality of slotted lugs 33 which are mounted onandextend inwardly from casing 10. As lugs 29 and tongues 33 cooperateto vertically guide and prevent rotation of rings 28, similarly tongues32 and lugs 33 cooperate to prevent rotation of ring 31 and to guide thelatter in its vertical movement. Interposed between the pressure andthrust rings 23 and 31 are a plurality of spaced compression springs 34which maintain rings 28 and 31 in spaced relationship and provide adownward thrust or biasing force upon each of the rollers 17 throughpressure ring 28. The compression of springs 34 or biasing force exertedby said springs is adjustable by means of a plurality of thrust ringhold-down assemblies 35 (FIG. 1) secured to casing 10, only one of whichassemblies is shown. Thrust ring hold-down assemblies 35, as best shownin FIG. 1A, comprise a housing having spaced parallel side walls 36which are secured, as by welding, to casing 10. A base plate 37 having acentral aperture 38A therein, is secured to casing 10 and to the lowerends of walls 36. A threaded stud 39A extends through aperture 38A intO'the housing and is connected to an anchor plate 40A which anchor plateis disposed between side walls 36 of the housing. A flexible tie-rodmember 41A, such as a woven-wire cable, is secured at one end to anchorplate 40A and extends at an angle upwardly into casing 10 and over thetop of tongue 32 of thrust ring 31 and downwardly to anchor plate 40Awhere the other end of the tierod member 41A is secured within theanchor plate. A guide rail 42A is provided on the inner surface of eachside Wall 36, which guide rails are adapted to engage grooves 43A in theopposite sides of anchor plate 40A. Adjacent the upper end of thehousing, a guide plate 44A is secured between side walls 36 and tocasing 10. Plate 44A is provided with two spaced holes 45A in which aresecured sealing tubes 45B. The sealing tubes 45B are adapted to receivetherethrough the legs of tie-rod mem-' ber 41A. An adjusting nut 46A isthreaded on the lower end of stud 39A and is held in a selected positionby a lock nut 47A. By loosening lock nut 47A and rotating a nut 46A onstud 39A, stud 39A is drawn downwardly or moved upwardly depending uponthe direction of rotation of nut 46A. Since anchor plate 40A is securedto stud 39A, anchor plate 40A is slid upwardly or downwardly along guiderails 42A. By rotating nut 46A on stud 39A in a direction so that stud39A. is moved downwardly, tierod member 41A is pulled downwardly byanchor plate 40A thereby drawing thrust ring 31 closer to pressure ring28 and increasing the compression of springs 34. Conversely, rotatingnut 46A in a direction so that stud 39A is allowed, under the urging ofsprings 34, to move upwardly, thrust ring 31 is permitted to move awayfrom pressure ring 28 thereby lessening the compression of springs 34.After the desired adjustment is made, lock nut 47A is tightened againstnut 46A to prevent rotation of the latter. By adjustment of thehold-down assemblies 35 in this manner, the crushing thrust upon rollers17 is adjustable. By reason of the vertical displacement of the innerand outer rings 19 and 20, the roller shaft 22 is supported at an angleto a horizontal plane which permits the crushing force or thrust to beexerted upon the rollers directly above the deepest part of grindingtrack 16.

Since rollers 17 support roller race member 18 and pressure ring 28, thecrushing force of the rollers includes the combined weight of each ofthe aforesaid members in addition to the downward force exerted bycompression springs 34. This crushing thrust is increased wheneverrollers 17 are forced upwardly by the material coming between therollers and track surfaces, which upward movement compresses throughpressure ring 28, springs 34.

The means by which pressure rollers 17 are rotatably mounted to theroller race member 18 are best shown in FIG. 3. Shaft 22 of roller 17carries on its outer end portion a bearing block 38 which is receivablebetween two spaced guide strips 39. Each strip 39 is secured by means ofbolts 40 to plates 41 which slope downwardly at the same angle as thelongitudinal axis of shaft 22 (FIG. 1). Plates 41 are in turn secured bywelding or other suitable means to the inner peripheral surface of outerring 20, and to a re-enforcing rib 42 (FIGS. 2 and 3) dis posed normalto said plates, and which re-enforcing ribs are secured to outer ring20. The lateral surfaces of block 38 abut the inner surfaces of strips39 and each strip 39 is provided along its top and bottom edges withinwardly projecting flanges 43. Block 38 is so formed that spaces 43Aare provided between the bottom surface of the block 38 and flanges 43to permit vertical movement between guide strips 39 and block 38, whichvertical movement is limited by flanges 43.

Shaft 22 carries at its inner end portion a second hearing block 44which is receivable between two spaced guide strips 45 (FIG. 1) and thelatter are suitably secured, as by bolts 46, to plates 47 (FIG. 2).Plates 47 are secured to the outer peripheral surface of inner ring 19and project outwardly thereof. Plates 47 are re-enforced by rib members48 secured normal to said plates and to the outer peripheral surface ofinner ring 19. Each strip 45 is provided with shoulders 49 along theinner vertical edge against which block 44 abuts.

In providing relative movement between strips 39 and block 38, verticalmovement of race member 18 with respect to rollers 17 is provided, whichmovement insures engagement of all the rollers with track 16 and thematerial to be pulverized under all normal operating conditions. Forexample, in the event there is uneven distribution of material to bepulverized in track 16 or one roller encounters material which will notreadily disintegrate, the roller which encounters that material willride upwardly lifting race member 18; when this occurs the other rollersare not lifted out of engagement with track 16 and the material to bepulverized by reason of the relative movement provided between the racemember and the rollers. In addition, rollers 17 will not only movevertically parallel to the axis of rotation of grinding table 14 underthe urging of material to be pulverized, but are also free to movewithin track 16 toward and away from the axis of rotation of grindingtable 14 under the urging of the material to be pulverized. Asillustrated in FIG. 4, if a particle P of material to be pulverizedwhich resists crushing lies in track 16 to the right of a vertical linedrawn from pressure ring 28, roller 17 will be urged toward the axis ofrotation of table 14 as shown by the dotted line. If a particle P ofmaterial to be pulverized which resists crushing lies in track 16 to theleft of a vertical line extending downwardly from pressure ring 28,roller 17 will be urged away from the axis of rotation of table 14, asshown by the dot-dash line. This movement of each of the rollers 17 isachieved because the opposite ends of shafts 22 of each of the rollersis supported by bearing blocks 38 and 44 which are free to movevertically relative to each other within the respective pairs of guidestrips 39 and 45, and since pressure ring 28 is free to move verticallyand laterally with respect to the roller race member 18.

Since pressure ring 28 and thrust ring 31 are mounted so as to permitvertical movement thereof with respect to the grinding ring table 14,and the rollers 17 are mounted to provide vertical movement of thelatter with respect to roller race member 18, sufficient yieldability isprovided in the assembly to prevent damage to the component partsthereof during the grinding operation. Furthermore, since the rollerssupport the pressure and thrust rings and roller race member 18 andsince the surfaces of the rollers and the track have complementaryshapes, a self-centering assembly is provided.

In the operation of the pulverizer of the present invention, table 14which carries grinding ring 14A is rotated by motor 15. Material to bepulverized, such as coal, cement clinkers or the like, is introducedinto casing 10 through feed tube 12. The material is discharged fromfeed tube 12 and falls through thrust ring 31, pressure ring 28 androller race member 18 onto the upper surface of table 14 and intogrinding track 16 as shown by the solid arrows in FIG. 1. As grindingring 14A rotates, it causes rollers 18 to revolve about the axis oftable 14 and the pressure exerted on rollers 18 by the weight of rings28 and 31 and by springs 34 through pressure ring 28, causes the rollersto rotate about their own axes. Rollers 18 thus planetate around theaxis of grinding table 14 and exert powerful crushing action on thematerial to be pulverized which lies on track 16. The interior of casing10 is provided with one or more air inlet ducts 50 (only one being shownin FIG. 1) disposed in the lower part of casing 10. An outlet opening 51is provided at the top of casing 10, which outlet communicates with anexhaust fan (not shown). As shown by the broken arrows in FIG. 1, air isdrawn into the interior of casing 10 through inlet duct 50 and upwardlypast the peripheral edge of table 14. As the air passes upwardly pasttable 14 and grinding ring 14A, the air entrains finely ground materialand carries the particles upwardly past the outer periphery of rings 28and 31 to the top of casing 10. Thereafter, the air and entrainedparticles pass adjustable vanes 52 into a classifying chamber 53 whereparticles of undesirable size separate from the air stream and arereturned to grinding ring 14A upon the opening of flap valves 54. Fromclassifying chamber 53 the air and the remaining entrained particlespass through outlet 51 to a point of use or storage (not shown).

Power consumption or input, and the output of the pulverizer accordingto this invention are dependent upon many factors, among which is therelationship between the diameter of the grinding track, the depth ofthe track, the diameter of the rollers and the curvature of the trackand of the rollers in a radial plane of the pulverizer. To provide apulverizer which is operable with a minimum of input (driving power)commensurate with a desirable output, the rollers 17 and grinding track16 are constructed in accordance with the following relationships (seeFIG. 4):

(a) =0e5 to 0.55 (b) =1.10

( =0J0 to 0.40

( -gi=1.30 to 2.00

where:

Dt is the mean diameter of the track,

Dr is the overall diameter of each roller,

d is the diameter of curvature of the grinding surface of a roller in aradial plane of the pulverizer,

Ds is the diameter of curvature of the track in a radial plane of thepulverizer, and

T is the depth of the track.

It is readily apparent from the foregoing description that a pulverizerhas been provided in which the grinding elements, grinding ring 14A,rollers 17, rings 28 and 31 coact and are so constructed to provide aself-centering assembly. Furthermore, the pulverizer according to thisinvention requires less power input than other ring and rollerpulverizers of comparable capacity. The novel mounting of the rollersand suspension of pressure and thrust rings, provide sufiicientyieldability between the component parts to prevent damage due to suddenstrain and stresses.

What is claimed is:

1. Pulverizing apparatus comprising a casing, a plate mounted forrotation and having a'grinding surface portion, means for rotating saidplate, means for introducing material to be pulverized into said casingand onto said plate and said grinding surface portion, a plurality ofrollers, each roller having a peripheral grinding face adapted forcontact with said grinding surface portion, support means for supportingeach roller for conjoined rotation about their respective axes, saidsupport means being carried by said rollers, the faces of said rollersand the grinding surface portion of said plate being shaped andproportioned to urge the faces of the rollers to constantly follow apredetermined path of contact on the grinding face portion, a first ringmember disposed above said rollers and adapted to engage said rollers, asecond ring member spaced from said first ring member and adapted toslidably engage said casing so that said second ring member is movablerelative to said first ring member, expansible and contractible meansdisposed between said first and second rings, a plurality of hold-downassemblies arranged in spaced relationship to each other, each of saidhold-down assemblies comprising a flexible cable, a plate slidablyconnected to the casing at a point below said second ring member, thecable being connected to said plate and to said second ring member,means for sliding said plate in a direction toward and away from saidsecond ring member so that said second ring member is moved inrelationship with the first ring member to thereby provide apredetermined biasing force on said rollers.

2. The apparatus of claim 1 wherein the flexible cable is U-shaped andthe ends of the cable are anchored in the plate with the looped endportion of the cable engaging said second ring member.

3. Pulverizing apparatus of the class described, comprising ahorizontally disposed grinding plate mounted for rotation and having anannular grinding surface provided with an arcuate depression, means forrotating the grinding plate, means for introducing material to bepulverized into said casing and in said arcuate depression, a rollerrace member disposed above and in'spaced relationship with the grindingplate, the roller race member having interconnected concentric inner andouter rings spaced from each other and lying in different horizontalplanes, three pairs of peripherally spaced guide strips secured to theinner and outer rings, each pair of guide strips of the inner and outerguide strips extend radially from their respective rings and toward thepair of guide strips on the other ring, three grinding rollers having aperipheral and arcuate grinding face adapted for movement within thearcuate depression and in contact therewith, the arcuate face of each ofthe rollers having a radius of curvature less than that of the arcuatedepression to provide contact of said grinding face with the deepestportion of the arcuate depression, each grinding roller having a shaft,a bearing block disposed on the opposite end portions of each of theroller shafts, each bearing block being receivable between a pair ofguide strips on the inner ring and a pair of guide strips on the outerring whereby the roller race is supported by the rollers, the bearingblocks and guide strips being constructed to permit vertical movement ofthe opposite ends of each of the roller shafts relative to each other sothat the arcuate faces of the rollers move within the arcuate depressionvertically and toward and away from the axis of rotation of the grindingplate under the urging of material to be pulverized, each pair of guidestrips on the inner ring having flanged opposite edge portions extendingover opposite edge portions of the bearing block disposed therebetweenand spaced from the latter to limit vertical movement of the bearingblock and roller shaft relative to the roller race member, means forexerting a biasing force on said rollers to urge the rollers inengagement with the arcuate depression.

4. Pulverizing apparatus comprising a casing, a grinding plate mountedfor rotation and having an annular grinding surface provided with anannular arcuate depression, means for rotating the grinding plate, meansfor introducing material to be pulverized into said casing and into saidarcuate depression, at least one roller having a shaft for rotatablymounting the roller, said roller having a peripheral and arcuategrinding face adapted for movement within the arcuate depression and incontact therewith, the roller shaft being supported at opposite ends foroscillatory movement in a vertical plane relative to the grinding plate,means exerting a biasing force on said rollers to maintain the latter inconstant engagement with the arcuate depression; and the grinding plateand roller being constructed in accordance with the followingrelationships:

Dr is the overall diameter of the roller,

d is the diameter of curvature of the arcuate grinding face of theroller,

and T is the depth of the arcuate depression, with the combination ofsaid various relationships selected so as to be mutually compatible.

References Cited in the file of this patent or the original patentUNITED STATES PATENTS 1,154,532 Moss Sept. 21, 1915 2,389,844 EbersoleNov. 27, 1945 FOREIGN PATENTS 201,726 Australia May 10, 1956 672,009Great Britain May 14, 1952

